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2948-SFP Vlan Trunk

2948-SFP Vlan Trunk

2948-SFP Vlan Trunk

We have a Vigor 3300V+ connected to a 2948-SFP.

3300 is capable of putting routing 4 subnets through one lan port into an 802.1q compliant switch.

I believe this is called a trunk?

We can get a ping accross all subnets each way using 4 seperate lan ports from the 3300 all untagged with a laptop plugged into each 3300 lan port.

From there we are stumped to get it all down one cable??

Tried tagged, untagged, making the vlan names the same as the 3300 etc.

Then went back to seperate lan ports from the 3300, created a second vlan on 2948 to split switch in half. Plugged lan1 from 3300 into vlan1 on 2948 and lan2 from 3300 into vlan2 but cannot get communicatiopn between the two????

If we use seperate switches from 2 lan ports it works!

Please help!!!!

RE: 2948-SFP Vlan Trunk

From your description, I get the impression you don't understand VLANs on 3COM switches. 3COM seems to have different descriptions of VLAN stuff depending on the data switch series. For instance, 3300 series versus anything Baseline, like the 2948-SFP+, 2924-SFP+, or 2226+. If you have not read the User Guide for the 3CBLSG48, you might want to do that, and compare it with the 3300 UG concerning VLANs, but that does not guaranty that things may function correctly. I have had various problems with the BaseLine series that seem to be hardware and software related. So you might want to look elsewhere now that HP has taken over the company.

One clue is that you only need an uplink trunk port to tie the switches, but do some reading and post back with some results.


RE: 2948-SFP Vlan Trunk

It sounds like the port you are plugging into the 3300 needs to be able to have subinterfaces created on it.  

On a cisco router, thats how you can have 1 port cable of routing 4 different subnets.

I pasted an example of one of my configs where I turned the lan port into 2 subinterfaces...maybe the config is similar on your 3300.

interface FastEthernet0/0
 description *** ! ***
 no ip address
 no ip mroute-cache
 speed 100
interface FastEthernet0/0.1
 description ** Data VLAN**
 encapsulation dot1Q 1 native
 ip address
 no ip mroute-cache
interface FastEthernet0/0.99
 description **Voice VLAN**
 encapsulation dot1Q 99
 ip address
 no ip mroute-cache

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